RESUMO
The objective of this study was to quantify the number and frequency of monocyte (MnOF) and multi-oocyte (MtOF) follicles in ovaries of bitches subjected to ovary salpingohysterectomy (OSH). Right and left ovaries of 38 bitches were collected after OSH, prepared, and a histological analysis was carried out. The ovaries were subjected to surface and deep histological cuts; the follicles were classified, and the number of follicles and cumulus oophorus complexes (COC) per follicle were quantified for each histological cut. MnOF and MtOF were found in all ovaries, at different developmental stages; primary follicles were grouped in the ovarian cortex, and follicles at other follicular stages presented a random distribution. MtOF containing two, three, four, or more COC were found in the ovaries of bitches, with a decreasing frequency trend, according to the number of COC in the MtOF. The effect of the age, number of estrus, estrus interval, and number of progenies per delivery was not significant for the number and frequency of MtOF in the ovaries of the bitches, whereas the size, number of pregnancies, use and number of contraceptive applications had some effect on the number and frequency of MtOF in the ovaries of the bitches.(AU)
Objetivou-se, com este estudo, quantificar o número e a frequência de folículos monocitários (MOF) e polioocitários (POF) provenientes de ovários de cadelas submetidas à ovariossalpingo-histerectomia (OSH). Para tanto, coletaram-se os ovários (direito e esquerdo) de 38 cadelas após OSH, com posterior preparação e análise histológica. Cada ovário foi submetido a dois cortes histológicos (superficial e profundo) onde se quantificou o número e a classificação dos folículos, bem como o número de complexos cumulus oophorus (COCs) por folículo em cada corte histológico. Observaram-se MOF e POF em todos os ovários estudados, em diferentes estádios de desenvolvimento, sendo os folículos primários agrupados no córtex ovariano, frente a uma distribuição aleatória dos outros estádios foliculares. FOPs contendo dois, três, quatro ou mais COCs foram observados nos ovários de todas as fêmeas estudadas, e sua frequência tendeu a diminuir de acordo com o número de COC presente no POF. Não se observou influência da idade, do número e do intervalo de estros, assim como do número de filhotes por gestação sobre o número/frequência de FOP nos ovários das cadelas estudadas, enquanto o porte, o número de gestações, o uso e o número de contraceptivo apresentaram algum grau de influência sobre o número/frequência de FOP nos ovários das cadelas estudadas.(AU)
Assuntos
Animais , Feminino , Gatos , Oócitos/classificação , Células do Cúmulo/classificação , Folículo Ovariano , Periodicidade , Ovariectomia/veterinária , Histerectomia/veterináriaRESUMO
The bitch is an experimental model of wild and even endangered canids. Therefore, the study of the factors that influence your fertility benefits scientific advances in both segments. Knowing that pyometra is one of the common uterine pathologies in bitches, this work aimed to evaluate the effects of pyometra on the morphology and competence of canine oocytes through the use of Azul Cresil Brilhante (ACB). For this purpose, 1197 canine oocytes that were divided into 2 groups classified as control (healthy) and treatment (pyometra). They were morphologically classified into grade 1 (G1), grade 2 (G2) and grade 3 (G3) and according to the ACB stain as ACB (+) and ACB () (not stained). Bitches in the healthy group had higher amounts of total oocytes (795) and better quality (495 oocytes G1) and competence (45 ± 9.8 ACB (+)). The use of ACB was useful to distinguish the competence of the studied oocytes and can be an auxiliary tool for choosing the best oocytes.
Assuntos
Animais , Feminino , Cães , Oócitos/classificação , Recuperação de Oócitos/veterinária , Piometra/complicações , Piometra/veterinária , Indicadores e ReagentesRESUMO
Traditional methods for the evaluation of oocyte quality are based on morphological classification of the follicle, cumulus-oocyte complex, polar body and meiotic spindle. This study is focused on the differences between the morphological assessment of oocyte quality, the assessment based on Lissamine Green B (LB) staining and the analysis of oocytes using a proteomic approach. We evaluated the effectiveness of electrochemical and chemical parthenogenetic activation under our laboratory conditions and evaluated the applicability of Lissamine Green B staining of cumulus-oocyte complexes (COCs) as a non-invasive method for predicting the maturational and developmental competence of porcine oocytes cultured in vitro. We determined that chemical parthenogenetic activation using ionomycin and 6-dimethylaminopurine was slightly more effective than electrochemical activation. After oocyte selection according to LB staining, we found significant differences (P 0.05) between the LB- group and LB+ group and the control group in their maturation, cleavage rate and rate of blastocysts. Proteomic analyses identified a selection of proteins that were differentially expressed in each group of analysed oocytes. Oocytes of the LB- group exhibited an increased variability of proteins involved in transcription regulation, proteosynthesis and the protein folding crucial for oocyte maturation and further embryonic development. These results found a better competence of LB- oocytes in maturation, cleavage and ability to reach the blastocyst stage.(AU)
Assuntos
Animais , Feminino , Suínos/embriologia , Suínos/fisiologia , Oócitos/classificação , Espectrometria de Massas , PartenogêneseRESUMO
Traditional methods for the evaluation of oocyte quality are based on morphological classification of the follicle, cumulus-oocyte complex, polar body and meiotic spindle. This study is focused on the differences between the morphological assessment of oocyte quality, the assessment based on Lissamine Green B (LB) staining and the analysis of oocytes using a proteomic approach. We evaluated the effectiveness of electrochemical and chemical parthenogenetic activation under our laboratory conditions and evaluated the applicability of Lissamine Green B staining of cumulus-oocyte complexes (COCs) as a non-invasive method for predicting the maturational and developmental competence of porcine oocytes cultured in vitro. We determined that chemical parthenogenetic activation using ionomycin and 6-dimethylaminopurine was slightly more effective than electrochemical activation. After oocyte selection according to LB staining, we found significant differences (P 0.05) between the LB- group and LB+ group and the control group in their maturation, cleavage rate and rate of blastocysts. Proteomic analyses identified a selection of proteins that were differentially expressed in each group of analysed oocytes. Oocytes of the LB- group exhibited an increased variability of proteins involved in transcription regulation, proteosynthesis and the protein folding crucial for oocyte maturation and further embryonic development. These results found a better competence of LB- oocytes in maturation, cleavage and ability to reach the blastocyst stage.
Assuntos
Feminino , Animais , Espectrometria de Massas , Oócitos/classificação , Partenogênese , Suínos/embriologia , Suínos/fisiologiaRESUMO
Quantitative real-time PCR (qPCR) is a valuable tool for gene expression studies and it is necessary to choose an ideal endogenous reference gene for data normalization. This work studied a set of reference genes in oocytes and cumulus cells of COCs (Cumulus-Oocyte Complexes) that are suitable for relative gene expression analyses after in vitro maturation (IVM) in bovine. Immature COCs were collected from ovaries of Nelore cattle (Bos indicus) and submitted to IVM. MII oocytes and cumulus cells were subjected to RNA extraction, reverse transcription and preamplification of cDNA. The expression level of eight reference genes (ACTB, GADPH, B2M, H2AFZ, GUSB, HPRT1, PPIA, and TBP) was measured by real time PCR and analyzed by geNorm software. The gene stability measure (M) was calculated and the ideal number of reference genes (RGs) was determined by the V value (pairwise variation). For oocyte samples, two RGs were the ideal number for relative quantification: HPRT1 and B2M and for bovine cumulus samples four were indicated: HPRT1, PPIA, B2M, and TBP genes. The normalization of a non-reference target gene (SOD1) by these reference genes was shown to be considerably different from normalization by less stable reference genes. Our results strengthen the importance of choosing good normalizing genes in order to analyze gene expression under specific experimental conditions and we suggest the use of these RGs in oocytes and cumulus cells of bovine cattle in in vitro matured COCs(AU)
Assuntos
Animais , Feminino , Bovinos , Expressão Gênica , Oócitos/classificação , Técnicas de Maturação in Vitro de Oócitos/veterinária , Reação em Cadeia da PolimeraseRESUMO
Quantitative real-time PCR (qPCR) is a valuable tool for gene expression studies and it is necessary to choose an ideal endogenous reference gene for data normalization. This work studied a set of reference genes in oocytes and cumulus cells of COCs (Cumulus-Oocyte Complexes) that are suitable for relative gene expression analyses after in vitro maturation (IVM) in bovine. Immature COCs were collected from ovaries of Nelore cattle (Bos indicus) and submitted to IVM. MII oocytes and cumulus cells were subjected to RNA extraction, reverse transcription and preamplification of cDNA. The expression level of eight reference genes (ACTB, GADPH, B2M, H2AFZ, GUSB, HPRT1, PPIA, and TBP) was measured by real time PCR and analyzed by geNorm software. The gene stability measure (M) was calculated and the ideal number of reference genes (RGs) was determined by the V value (pairwise variation). For oocyte samples, two RGs were the ideal number for relative quantification: HPRT1 and B2M and for bovine cumulus samples four were indicated: HPRT1, PPIA, B2M, and TBP genes. The normalization of a non-reference target gene (SOD1) by these reference genes was shown to be considerably different from normalization by less stable reference genes. Our results strengthen the importance of choosing good normalizing genes in order to analyze gene expression under specific experimental conditions and we suggest the use of these RGs in oocytes and cumulus cells of bovine cattle in in vitro matured COCs
Assuntos
Feminino , Animais , Bovinos , Expressão Gênica , Oócitos/classificação , Reação em Cadeia da Polimerase , Técnicas de Maturação in Vitro de Oócitos/veterináriaRESUMO
The magnitude of oocytes role for embryo development is categorical. This unique cell contains the machineries and cellular components necessary to remodel male and female chromatin, to sustain early development and to, ultimately, generate a complete and complex individual. However, to gain these competences before fertilization, the oocyte undergoes several morphological, cellular and molecular changes during its lifetime enclosed in the ovarian follicle. This review will briefly revisit how the oocyte orchestrate the follicular cells, and how molecules transit to the oocyte from the innermost (cumulus) and outermost (antrum and granulosa cells) layers surrounding the follicle-enclosed oocyte. Finally, we will discuss the interferences of in vitro culture conditions in the communication of the oocyte with its surrounding cells and the potential strategies to modulate these communication systems to increase oocyte competence.(AU)
Assuntos
Folículo Ovariano/anatomia & histologia , Folículo Ovariano/crescimento & desenvolvimento , Vesículas Extracelulares , Oócitos/classificaçãoRESUMO
The magnitude of oocytes role for embryo development is categorical. This unique cell contains the machineries and cellular components necessary to remodel male and female chromatin, to sustain early development and to, ultimately, generate a complete and complex individual. However, to gain these competences before fertilization, the oocyte undergoes several morphological, cellular and molecular changes during its lifetime enclosed in the ovarian follicle. This review will briefly revisit how the oocyte orchestrate the follicular cells, and how molecules transit to the oocyte from the innermost (cumulus) and outermost (antrum and granulosa cells) layers surrounding the follicle-enclosed oocyte. Finally, we will discuss the interferences of in vitro culture conditions in the communication of the oocyte with its surrounding cells and the potential strategies to modulate these communication systems to increase oocyte competence.
Assuntos
Folículo Ovariano/anatomia & histologia , Folículo Ovariano/crescimento & desenvolvimento , Vesículas Extracelulares , Oócitos/classificaçãoRESUMO
Nos trópicos, o uso de raças adaptadas tem sido uma estratégia para minimizar o efeito do estresse térmico calórico (ETC). No entanto, faltam informações que quantifiquem o estresse e o seu efeito sobre a reprodução dessas raças. O objetivo deste estudo foi avaliar a qualidade do oócito recuperado e alguns parâmetros fisiológicos indicadores de ETC em bovinos de raças adaptadas. Animais Bos taurus x Bos indicus (n=6) e Bos taurus (raça Pantaneira; n=12), localizados na região de transição entre o Cerrado e o Pantanal brasileiro, foram submetidos à aspiração folicular guiada por ultrassonografia (OPU) em diferentes condições climáticas. Foram realizadas oito sessões de OPU, com intervalo mínimo de sete dias e máximo de 54 dias entre as coletas. Para caracterização climática, foi realizado o cálculo do índice de temperatura e umidade (ITU). Foram quantificados os ITUs do dia da OPU, sete dias antes e 60 dias antes de cada sessão. Os parâmetros fisiológicos e a viabilidade oocitária de fêmeas das raças Girolando e Pantaneira não foram afetados negativamente por ITUs entre 72 e 78. O ETC crônico (60 dias) parece afetar a viabilidade oocitária de doadoras na raça Pantaneira quando ITU é superior a 75.(AU)
In tropical regions, the use of adapted breeds has been a strategy to minimize the effect of heat stress (HS) in cattle. However, information quantifying stress and its effect on reproduction of these breeds is lacking. The aim of this study was to evaluate the quality of the recovered oocyte and some physiological parameters that indicate HS in adapted breed. Bos taurus x Bos indicus (n=6) and Pantaneira (n=12) cows, located in the transition region between Cerrado and Brazilian Pantanal, underwent follicular aspiration guided by ultrasound (OPU) in different weather conditions. Eight sessions of OPU were carried out, with a minimum interval of 7 days and maximum 54 days between sessions. For weather characterization, the temperature and humidity index (THI) was calculated. THI of the day of OPU, 7 days before and 60 days before each session were calculated. The physiological parameters and oocyte viability of Girolando and Pantaneira cows were not negatively influenced under ITU between 72 and 78. The chronic HS (60 days)may affect the oocyte viability of Pantaneira donors when ITU is over 75.(AU)
Assuntos
Animais , Bovinos , Bovinos/embriologia , Transtornos de Estresse por Calor/veterinária , Oócitos/classificação , UltrassonografiaRESUMO
Nos trópicos, o uso de raças adaptadas tem sido uma estratégia para minimizar o efeito do estresse térmico calórico (ETC). No entanto, faltam informações que quantifiquem o estresse e o seu efeito sobre a reprodução dessas raças. O objetivo deste estudo foi avaliar a qualidade do oócito recuperado e alguns parâmetros fisiológicos indicadores de ETC em bovinos de raças adaptadas. Animais Bos taurus x Bos indicus (n=6) e Bos taurus (raça Pantaneira; n=12), localizados na região de transição entre o Cerrado e o Pantanal brasileiro, foram submetidos à aspiração folicular guiada por ultrassonografia (OPU) em diferentes condições climáticas. Foram realizadas oito sessões de OPU, com intervalo mínimo de sete dias e máximo de 54 dias entre as coletas. Para caracterização climática, foi realizado o cálculo do índice de temperatura e umidade (ITU). Foram quantificados os ITUs do dia da OPU, sete dias antes e 60 dias antes de cada sessão. Os parâmetros fisiológicos e a viabilidade oocitária de fêmeas das raças Girolando e Pantaneira não foram afetados negativamente por ITUs entre 72 e 78. O ETC crônico (60 dias) parece afetar a viabilidade oocitária de doadoras na raça Pantaneira quando ITU é superior a 75.(AU)
In tropical regions, the use of adapted breeds has been a strategy to minimize the effect of heat stress (HS) in cattle. However, information quantifying stress and its effect on reproduction of these breeds is lacking. The aim of this study was to evaluate the quality of the recovered oocyte and some physiological parameters that indicate HS in adapted breed. Bos taurus x Bos indicus (n=6) and Pantaneira (n=12) cows, located in the transition region between Cerrado and Brazilian Pantanal, underwent follicular aspiration guided by ultrasound (OPU) in different weather conditions. Eight sessions of OPU were carried out, with a minimum interval of 7 days and maximum 54 days between sessions. For weather characterization, the temperature and humidity index (THI) was calculated. THI of the day of OPU, 7 days before and 60 days before each session were calculated. The physiological parameters and oocyte viability of Girolando and Pantaneira cows were not negatively influenced under ITU between 72 and 78. The chronic HS (60 days)may affect the oocyte viability of Pantaneira donors when ITU is over 75.(AU)
Assuntos
Animais , Bovinos , Oócitos/classificação , Bovinos/embriologia , Transtornos de Estresse por Calor/veterinária , UltrassonografiaRESUMO
The aim was to evaluate the quantity and quality of immature oocytes obtained from bovine ovarieswith high and low antral follicle count (AFC). Therefore, ovaries were obtained from a slaughterhouse and thelaboratory were divided in two groups: high count (HC: ≥ 20) and low count (LC: 0.05). Therefore, it is concluded that the AFC does not influence thequantity and quality of oocytes.
Assuntos
Feminino , Animais , Bovinos , Bovinos/fisiologia , Oócitos/classificação , Técnicas de Cultura EmbrionáriaRESUMO
The aim was to evaluate the quantity and quality of immature oocytes obtained from bovine ovarieswith high and low antral follicle count (AFC). Therefore, ovaries were obtained from a slaughterhouse and thelaboratory were divided in two groups: high count (HC: ≥ 20) and low count (LC: <20) follicles. After thefollicular aspiration, retrieved oocytes were assessed by morphological appearance and brilliant cresyl blue test(BCB) in viable and non-viable. The data were analyzed by Fischer exact test (P < 0.05). After three replicates,85 ovaries were recovered and distributed between the groups HC (22) and LC (63). There was no significantdifference in the recovery rate. Furthermore, in the morphology and BCB test the viability rates werestatistically similar between groups (P > 0.05). Therefore, it is concluded that the AFC does not influence thequantity and quality of oocytes.(AU)
Assuntos
Animais , Feminino , Bovinos , Bovinos/fisiologia , Oócitos/classificação , Técnicas de Cultura EmbrionáriaRESUMO
Reproductive technologies to synchronize estrus and ovulation in cattle have enhanced the ability to practically utilize artificial insemination to increase both genetic merit and reproductive management of beef and dairy herds. The ability to successfully synchronize a follicular wave and ovulation, in heifers and cows, has improved substantially in recent years. Consequently, pregnancy rates to a single fixed-time artificial insemination (FTAI) can approximate that of insemination following spontaneous estrus. Despite these advances, a subset of heifers and cows often has a physiologically immature dominant follicle at the time of GnRH-induced ovulation. These animals will exhibit reduced pregnancy rates and decreased embryonic survival if a pregnancy happens to become established. The physiological mechanisms underlying the preceding decreased fertility have been a focus of our laboratories and may include an effect of the follicular microenvironment on both oocyte competence and the maternal environment. Oocytes must have adequate opportunity to complete cytoplasmic and molecular maturation during the final stages of oocyte maturation that occur within the preovulatory follicle. Follicular status, during the proestrus period, must be such that adequate circulating concentrations of estradiol are present before FTAI to increase oviductal transport of gametes and enhance both the luteinizing capacity of granulosa cells and progesterone receptor population in the post-ovulatory uterus. Following ovulation, the follicles transformation to a functional corpus luteum to secrete adequate amounts of progesterone is essential for the establishment of pregnancy. The physiological status of the preovulatory follicle, prior to FTAI, greatly affects the concepts discussed above and has an important impact on pregnancy establishment and maintenance in cattle.
Assuntos
Feminino , Animais , Gravidez , Bovinos , Bovinos/embriologia , Folículo Ovariano/embriologia , Oócitos/classificação , Técnicas ReprodutivasRESUMO
This review aims at giving an overview on the physiological events leading to puberty onset in mammals and more specifically in cattle. Puberty is an important developmental milestone in mammals involving numerous changes in various physiological regulations and behaviors. It is a physiological unique event integrating several important central regulations at the crossroad of adaptation to environment: reproductive axis, feeding behavior and nutritional controls, growth, seasonal rhythm and stress. Puberty onset is also an important economic parameter in replacement heifer program and in genomic selection (genomic bulls). The quest for advanced puberty onset should be carefully balanced by its impact on physiological parameters of the animal and its offspring. Thus one has to carefully consider each step leading to puberty onset and set up a strategy that will lead to early puberty without being detrimental in the long term. In this review, major contributions in the understanding of puberty process obtained in rodents, primates and farm animals such as sheep and cattle are discussed. In the first part we will detail the endocrine events leading to puberty onset with a special focus on the regulation of GnRH secretion. In the second part we will describe the neural mechanisms involved in silencing and reactivating the GnRH neuronal network.
Assuntos
Hormônio Liberador de Gonadotropina , Maturidade Sexual/genética , Oócitos/classificação , Oócitos/crescimento & desenvolvimento , Hipotálamo , NeuroendocrinologiaRESUMO
Reproductive technologies to synchronize estrus and ovulation in cattle have enhanced the ability to practically utilize artificial insemination to increase both genetic merit and reproductive management of beef and dairy herds. The ability to successfully synchronize a follicular wave and ovulation, in heifers and cows, has improved substantially in recent years. Consequently, pregnancy rates to a single fixed-time artificial insemination (FTAI) can approximate that of insemination following spontaneous estrus. Despite these advances, a subset of heifers and cows often has a physiologically immature dominant follicle at the time of GnRH-induced ovulation. These animals will exhibit reduced pregnancy rates and decreased embryonic survival if a pregnancy happens to become established. The physiological mechanisms underlying the preceding decreased fertility have been a focus of our laboratories and may include an effect of the follicular microenvironment on both oocyte competence and the maternal environment. Oocytes must have adequate opportunity to complete cytoplasmic and molecular maturation during the final stages of oocyte maturation that occur within the preovulatory follicle. Follicular status, during the proestrus period, must be such that adequate circulating concentrations of estradiol are present before FTAI to increase oviductal transport of gametes and enhance both the luteinizing capacity of granulosa cells and progesterone receptor population in the post-ovulatory uterus. Following ovulation, the follicles transformation to a functional corpus luteum to secrete adequate amounts of progesterone is essential for the establishment of pregnancy. The physiological status of the preovulatory follicle, prior to FTAI, greatly affects the concepts discussed above and has an important impact on pregnancy establishment and maintenance in cattle.(AU)
Assuntos
Animais , Feminino , Gravidez , Bovinos , Bovinos/embriologia , Folículo Ovariano/embriologia , Oócitos/classificação , Técnicas ReprodutivasRESUMO
This review aims at giving an overview on the physiological events leading to puberty onset in mammals and more specifically in cattle. Puberty is an important developmental milestone in mammals involving numerous changes in various physiological regulations and behaviors. It is a physiological unique event integrating several important central regulations at the crossroad of adaptation to environment: reproductive axis, feeding behavior and nutritional controls, growth, seasonal rhythm and stress. Puberty onset is also an important economic parameter in replacement heifer program and in genomic selection (genomic bulls). The quest for advanced puberty onset should be carefully balanced by its impact on physiological parameters of the animal and its offspring. Thus one has to carefully consider each step leading to puberty onset and set up a strategy that will lead to early puberty without being detrimental in the long term. In this review, major contributions in the understanding of puberty process obtained in rodents, primates and farm animals such as sheep and cattle are discussed. In the first part we will detail the endocrine events leading to puberty onset with a special focus on the regulation of GnRH secretion. In the second part we will describe the neural mechanisms involved in silencing and reactivating the GnRH neuronal network.(AU)
Assuntos
Maturidade Sexual/genética , Oócitos/classificação , Oócitos/crescimento & desenvolvimento , Hormônio Liberador de Gonadotropina , Neuroendocrinologia , HipotálamoRESUMO
From an evolutionary point of view, the gametes are the cells in the body that matter the most as they are the ones who transmit their genes to the next generation ensuring continuation of the species. Being able to generate mature oocytes in vitro is of great interest. Oocytes are the key to totipotency and are able to reprogram somatic cells in approximately one day. In addition, in contrast to a clump of pluripotent stem cells, once the developmental program has started, fertilized oocytes develop into a clump of cells with positional in formation and the possibility to differentiate into both the embryonic and the extraembryonic lineages that form a complete developing and viable organism. How to instruct pluripotent stem cells to become oocytes in vitrois still unclear and even though the first steps to obtain mouse oocytes have recently been successfully demonstrated, inducing meiosis progression and folliculogenesis in vitro are still far from being understood and have not yet been accomplished. In humans, the specific molecular niche that leads to correct oogenesis is less understood. Here, we discuss the current status of in vitro differentiation of human pluripotent stem cells into gametes, in particular to oocytes.(AU)
Assuntos
Humanos , Oócitos/classificação , Técnicas In Vitro , Células Germinativas , Diferenciação CelularRESUMO
From an evolutionary point of view, the gametes are the cells in the body that matter the most as they are the ones who transmit their genes to the next generation ensuring continuation of the species. Being able to generate mature oocytes in vitro is of great interest. Oocytes are the key to totipotency and are able to reprogram somatic cells in approximately one day. In addition, in contrast to a clump of pluripotent stem cells, once the developmental program has started, fertilized oocytes develop into a clump of cells with positional in formation and the possibility to differentiate into both the embryonic and the extraembryonic lineages that form a complete developing and viable organism. How to instruct pluripotent stem cells to become oocytes in vitrois still unclear and even though the first steps to obtain mouse oocytes have recently been successfully demonstrated, inducing meiosis progression and folliculogenesis in vitro are still far from being understood and have not yet been accomplished. In humans, the specific molecular niche that leads to correct oogenesis is less understood. Here, we discuss the current status of in vitro differentiation of human pluripotent stem cells into gametes, in particular to oocytes.
Assuntos
Humanos , Células Germinativas , Diferenciação Celular , Oócitos/classificação , Técnicas In VitroRESUMO
OBJECTIVE: To evaluate the impact of oocyte maturational stage at retrieval on embryo multinucleation. DESIGN: Retrospective study. SETTING: Private institution for assisted reproduction. PATIENT(S): A total of 412 patients undergoing 500 intracytoplasmic sperm injection (ICSI) cycles between August 2006 and September 2010. INTERVENTION(S): Routine ICSI laboratory procedures. MAIN OUTCOME MEASURE(S): Normal and abnormal fertilization; embryo development; arrest at pronuclear stage; failure to undergo first mitotic division; presence of embryo multinucleation; embryo quality; pregnancy, implantation, and miscarriage rates. RESULT(S): A significantly lower percentage of multinucleation was found in embryos originating from metaphase II (MII) oocytes when compared with MI-II- and MI-derived oocytes. Significantly fewer multinucleated cells per embryo were observed in MII-derived oocytes. Clinical pregnancy and implantation rates were significantly higher when only embryos derived from MII oocytes were transferred. CONCLUSION(S): Embryo multinucleation rate increases when in vitro-matured (2-5 hours incubation) MI (MI-II) oocytes are used instead of in vivo-matured oocytes in ICSI. Furthermore, all other ICSI outcome parameters are also compromised. The use of donated gametes does not modify these results.
Assuntos
Núcleo Celular/patologia , Embrião de Mamíferos/citologia , Desenvolvimento Embrionário , Infertilidade/terapia , Metáfase , Oócitos/patologia , Oócitos/transplante , Aborto Espontâneo/epidemiologia , Adulto , Argentina/epidemiologia , Comorbidade , Implantação do Embrião , Indução Embrionária , Feminino , Humanos , Infertilidade/epidemiologia , Oócitos/classificação , Indução da Ovulação , Gravidez , Resultado da Gravidez , Prevalência , Estudos Retrospectivos , Injeções de Esperma Intracitoplásmicas , Resultado do TratamentoRESUMO
O objetivo do presente trabalho, foi o estudo dos efeitos da idade e da fase do ciclo estral dos bovinos na quantidade e qualidade de ovócitos e de embriões produzidos in vitro. Para isso, foram utilizados ovócitos de 63 vacas da raça Holstein-Friesian abatidas em matadouro, com idades compreendidas entre 1 e 15 anos, as quais foram divididas em 5 lotes de acordo com a idade. Cada lote foi subdividido de acordo com a fase do ciclo estral em que o animal se encontrava no dia do abate, pela presença ou não de corpo lúteo funcional na superfície do ovário. Os lotes referentes à idade foram: <2; [2,4]; [5,6]; [7, 8] e >8 anos. Após punção dos folículos, os ovócitos foram divididos nas classes A, B, C e D, tendo em conta o seu aspecto morfológico, em que apenas os de classe A e B foram usados para a FIV. Observou-se que o número de ovócitos produzidos foi diretamente proporcional à idade das vacas (R=0,99 - P<0,001). Quanto à fase do ciclo estral, as vacas em fase luteínica, produziram maior número de ovócitos que as vacas em fase folicular (P<0,001), respetivamente 7,05 ± 0,11 e 10,87 ± 1,01. Relativamente à qualidade dos ovócitos em função da idade das vacas, observou-se uma correlação positiva (R = 0,94 p<0,01) até aos [7, 8] anos, começando a baixar a partir desta idade. As vacas em fase luteínica produziram ovócitos de melhor qualidade relativamente às vacas em fase folicular (6,77 ± 0,64 e 3,84± 0,64; respetivamente). Quanto à quantidade de zigotos que clivaram, esta foi superior para os lotes de vacas em fase luteínica em comparação com os de vacas em fase folicular (59,03% e 45,52%; respetivamente), observando-se ainda que as vacas em fase luteínica produziram igualmente, em geral, maior número de embriões aos 7 dias após FIV que as vacas em fase folicular(44,23% e 31,48%; respetivamente). Os resultados do presente trabalho permitem concluir que existe uma estreita relação entre a idade e a fase do ciclo estral das vacas e a quantidade e ...
The aim of the present study was the evaluation of whether the age or the estrous cycle phase would influence the quantity and/or quality of oocytes and in vitro embryo production. Oocytes from ovaries of 63 Holstein- Friesian slaughtered cows, aging between 1 and 15 years old, were divided into 5 groups considering their age and then subdivided according to their phase of estrous cycle. The groups were: <2; [2, 4]; [5, 6]; [7, 8] and >8 years old. The estrous cycle phase (lutheal or follicular) was evaluated by the presence or absence of a functional corpus luteum. The cumulus-oocyte-complex (COCs) was divided in classes A, B, C and D according to their morphological aspect. The COCs classed as C and D were excluded, being the COCs classed as A and B matured in vitro and fertilized. As result of the study, it was observed that the number of total produced COCs was directly proportional to the age of the cow (R=0,99 - P<0,001). It has also noticed that cows in the lutheal phase produced more COCs than cows in the follicular phase (P<0,001), respectively 7,05 ± 0,11 and 10,87 ± 1,01. The COCs quality augmented from the group of cows aging less than 2 years to cows aging between [7, 8] years old, with a positive correlation (R = 0.94 p<0.01) starting then to decrease. It was also realized that cows in the lutheal phase produced better COCs quality than cows in the follicular phase (6,77 ± 0,64 e 3,84± 0,64; respectively). In what cleavage rate is concerned, better results were achieve with cows in lutheal phase (59,03%) then in follicular phase (45,52%). It was also possible to notice a better embryo production in cows in the lutheal phase (44,23%) then cows in the follicular phase. The results of the present study allow to conclude that there is a relation between the age and the estrous cycle stage in the quality and quantity of COCs and in vitro produced bovine embryos...